Immersion exposure apparatus and device fabricating method with two substrate stages and metrology station

ABSTRACT

The present invention provides an exposure apparatus can suppress the occurrence of residual liquid. An exposure apparatus comprises: a first stage that holds the substrate and is movable; a second stage that is movable independently of the first stage; and a liquid immersion mechanism that forms a liquid immersion region of a liquid on an upper surface of at least one stage of the first stage and the second stage; wherein, a recovery port that is capable of recovering the liquid is provided to the upper surface of the second stage.

This is a Divisional of U.S. patent application Ser. No. 11/666,420,filed Apr. 27, 2007 now U.S. Pat. No. 8,330,939 is the U.S. NationalStage of International Application No. PCT/JP2005/020020 filed Oct. 31,2005. The disclosure of each of the above-identified applications isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an exposure apparatus that exposes asubstrate through a projection optical system, and a device fabricatingmethod.

The present application claims priority to Patent Application No.2004-318017 filed on Nov. 1, 2004, and the contents thereof areincorporated herein by reference.

BACKGROUND ART

The process of photolithography, which is one of the processes formanufacturing a microdevice such as a semiconductor device and a liquidcrystal display device, uses an exposure apparatus that projects theimage of a pattern formed on a mask onto a photosensitive substrate.This exposure apparatus comprises a mask stage that supports a mask aswell as a substrate stage that supports a substrate, and projects animage of the pattern of the mask onto the substrate through a projectionoptical system while successively moving the mask stage and thesubstrate stage. In addition, there are exposure apparatuses that aredesigned, for example, to improve throughput by providing twoindependently moveable stages on the image plane side of the projectionoptical system. In microdevice fabrication, there is a demand toincrease the fineness of the patterns formed on substrates in order toincrease device density. To meet this demand, it is preferable tofurther increase the resolution of exposure apparatuses. As one means toachieve this increase in resolution, an immersion exposure apparatus hasbeen proposed, as disclosed in Patent Document 1 below, that forms aliquid immersion region by filling a liquid between the projectionoptical system and the substrate, and performs an exposure processthrough the liquid of that liquid immersion region.

-   Patent Document 1: PCT International Publication No. WO 99/49504

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

In an immersion exposure apparatus, there are cases (for example, duringmaintenance) wherein it is desired to recover all of the liquid of theliquid immersion region. In such a case, if the liquid is not fullyrecovered and some remains, then there is a possibility that theresidual liquid will scatter to the various equipment that constitutethe exposure apparatus and adversely affect that equipment. In addition,there is a risk that the residual liquid will cause fluctuations in theenvironment (for example, its humidity) wherein the exposure apparatusis disposed, and thereby adversely affect, for example, exposure andmeasurement accuracies.

A purpose of some aspects of the invention is to provide an exposureapparatus that can maintain a desired performance by suppressing theoccurrence of residual liquid, and a device fabricating method.

Means for Solving the Problem

A first aspect of the present invention provides an exposure apparatusthat exposes a substrate through a projection optical system,comprising: a first stage that holds the substrate and is movable withina two dimensional plane on the image plane side of the projectionoptical system that is substantially parallel to the image plane; asecond stage that is movable independently of the first stage within atwo dimensional plane on the image plane side of the projection opticalsystem that is substantially parallel to the image plane; and a liquidimmersion mechanism that forms a liquid immersion region of a liquid onan upper surface of at least one stage of the first stage and the secondstage; wherein, a recovery port that is capable of recovering the liquidis provided to or in the vicinity of the upper surface of the secondstage.

According to the first aspect of the invention, the recovery port thatrecovers the liquid is provided to or in the vicinity of the uppersurface of the second stage, which is disposed on the image plane sideof the projection optical system, and it is therefore possible tosatisfactorily recover the liquid and to suppress the occurrence ofresidual liquid.

A second aspect of the present invention provides a device fabricatingmethod, wherein an exposure apparatus according to the above aspect isused.

According to the second aspect of the invention, it is possible tofabricate a device with an exposure apparatus that maintains a desiredperformance.

Effects of the Invention

According to the present invention, it is possible to suppress theoccurrence of residual liquid, and to perform the exposure process andthe measurement process with good accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram that shows the exposure apparatusaccording to a first embodiment.

FIG. 2 is a cross sectional view of a substrate stage.

FIG. 3 is a plan view of the substrate stage.

FIG. 4 is a cross sectional view of a measurement stage.

FIG. 5 is a plan view of the measurement stage.

FIG. 6 is a plan view of the substrate stage and the measurement stage,viewed from above.

FIG. 7A is for explaining the operation of the substrate stage and themeasurement stage.

FIG. 7B is for explaining the operation of the substrate stage and themeasurement stage.

FIG. 8A is for explaining the operation of the substrate stage and themeasurement stage.

FIG. 8B is for explaining the operation of the substrate stage and themeasurement stage.

FIG. 9 is for explaining the state wherein the liquid immersion area ismoving.

FIG. 10 is for explaining the state wherein the liquid of the liquidimmersion area is being recovered.

FIG. 11 shows the exposure apparatus according to a second embodiment.

FIG. 12 shows the exposure apparatus according to a third embodiment.

FIG. 13 shows the exposure apparatus according to a fourth embodiment.

FIG. 14 shows the exposure apparatus according to a fifth embodiment.

FIG. 15 is a flow chart diagram that depicts one example of a processfor fabricating a microdevice.

BEST MODE FOR CARRYING OUT THE INVENTION

The following explains the embodiments of the present invention,referencing the drawings, but the present invention is not limitedthereto.

First Embodiment

FIG. 1 is a schematic block diagram that shows an exposure apparatusaccording to a first embodiment. In FIG. 1, an exposure apparatus EXcomprises: a movable mask stage MST that holds a mask M; a movablesubstrate stage ST1 that holds a substrate P; a movable measurementstage ST2 on which measuring instruments that perform measurementsrelated to an exposure process are mounted; an illumination opticalsystem IL that illuminates the mask M supported by the mask stage MSTwith exposure light EL; a projection optical system PL, which projectsan image of the pattern of the mask M illuminated by the exposure lightEL onto the substrate P held by the substrate stage ST1; and a controlapparatus CONT that performs supervisory control of the entire operationof the exposure apparatus EX. The substrate stage ST1 and themeasurement stage ST2, which are each movably supported on a base memberBP, are independently movable. A gas bearing 141 that noncontactuallysupports the substrate stage ST1 on an upper surface BT of the basemember BP is provided to a lower surface U1 of the substrate stage ST1.Likewise, a gas bearing 142 for noncontactually supporting themeasurement stage ST2 on the upper surface BT of the base member BP isprovided to a lower surface U2 of the measurement stage ST2. Thesubstrate stage ST1 and the measurement stage ST2 are each independentlymovable within a two dimensional plane (XY plane) on the image planeside of the projection optical system PL that is substantially parallelto that image plane.

The exposure apparatus EX of the present embodiment is a liquidimmersion exposure apparatus that adapts the liquid immersion method tosubstantially shorten the exposure wavelength, improve the resolution,as well as substantially increase the depth of focus, and comprises aliquid immersion mechanism 1 for forming a liquid immersion region LR ofa liquid LQ on the image plane side of the projection optical system PL.The liquid immersion mechanism 1 comprises: a nozzle member 70, which isprovided in the vicinity of the image plane side of the projectionoptical system PL, has supply ports 12 that supply the liquid LQ andrecovery ports 22 that recover the liquid LQ; a liquid supply mechanism10 that supplies the liquid LQ to the image plane side of the projectionoptical system PL through the supply ports 12 provided to the nozzlemember 70; and a liquid recovery mechanism 20 that recovers the liquidLQ on the image plane side of the projection optical system PL throughthe recovery ports 22 provided to the nozzle member 70. The nozzlemember 70 is annularly formed so that it surrounds a tip portion of theprojection optical system PL on the image plane side. At least duringthe projection of the image of the pattern of the mask M onto thesubstrate P; the liquid immersion mechanism 1 uses the liquid LQ that issupplied by the liquid supply mechanism 10 to locally form the liquidimmersion region LR of the liquid LQ, which is larger than a projectionarea AR and smaller than the substrate P, on one part of the substrate Pthat includes the projection area AR of the projection optical systemPL. Specifically, the exposure apparatus EX employs a local liquidimmersion system that fills the liquid LQ in the space of the opticalpath that is between a lower surface LSA of a first optical element LS1,which is closest to the image plane of the projection optical system PL,and one part of the upper surface of the substrate P that is disposed onthe image plane side of the projection optical system PL, and thenexposes the substrate P by projecting a pattern of the mask M onto thesubstrate P by irradiating such with the exposure light EL that passesthrough the mask M via the projection optical system PL and the liquidLQ that forms the liquid immersion region LR.

In addition, the liquid immersion mechanism 1 can locally form theliquid immersion region LR of the liquid LQ not just on the uppersurface of the substrate P, but also on at least one of an upper surfaceF1 of the substrate stage ST1 and an upper surface F2 of the measurementstage ST2. Furthermore, recovery ports 51 that can recover at least partof the liquid LQ of the liquid immersion region LR are provided to themeasurement stage ST2.

Furthermore, the liquid immersion mechanism 1 is not limited to the onedisclosed in the present embodiment, and various aspects can beemployed. For example, it is possible to employ the liquid immersionmechanism disclosed in, for example, U.S. Patent Publication No.2004/0160582.

The present embodiment will now be explained as exemplified by a casewherein a scanning type exposure apparatus (a so-called scanningstepper) is used as the exposure apparatus EX that projects an image ofthe pattern formed on the mask M onto the substrate P whilesynchronously moving the mask M and the substrate P in mutuallydifferent scanning directions (reverse directions). In the followingexplanation, the directions in which the mask M and the substrate Psynchronously move within the horizontal plane are the X axialdirections (scanning directions), the directions orthogonal to the Xaxial directions within the horizontal plane are the Y axial directions(non-scanning directions), and the directions that are perpendicular tothe X and Y axial directions and that coincide with an optical axis AXof the projection optical system PL are the Z axial directions. Inaddition, the rotational (inclined) directions about the X, Y, and Zaxial directions and the θX, θY, and θZ directions, respectively.Furthermore, “substrate” herein includes one wherein the substrate, forexample, a semiconductor wafer is coated with a photosensitive material(photoresist), and “mask” includes a reticle wherein a device pattern isformed that is reduction projected onto the substrate.

The substrate stage ST1 and the measurement stage ST2 are each movableby the drive of a drive mechanism SD that includes, for example, alinear motor. By controlling the drive mechanism SD, the controlapparatus CONT can move the substrate stage ST1 and the measurementstage ST2 together in the XY plane while maintaining a prescribed state,wherein the upper surface F1 of the substrate stage ST1 and the uppersurface F2 of the measurement stage ST2 are proximate (close) to or incontact with one another in a prescribed area that includes the areadirectly below the projection optical system PL. By moving the substratestage ST1 together with the measurement stage ST2, the control apparatusCONT can move the liquid immersion region LR between the upper surfaceF1 of the substrate stage ST1 and the upper surface F2 of themeasurement stage ST2 in a state wherein the liquid LQ is retainedbetween the projection optical system PL and at least one of the uppersurface F1 of the substrate stage ST1 and the upper surface F2 of themeasurement stage ST2.

In addition, a protruding portion (overhanging portion) H1, whichprojects toward the measurement stage ST2, is provided on the +Y side ofthe substrate stage ST1, and a recessed portion 54 that corresponds tothe overhanging portion H1 is provided on the −Y side of the measurementstage ST2. Furthermore, the overhanging portion H1 is also provided onthe −Y side of the substrate stage ST1. Furthermore, the +Y side area ofthe upper surface of the substrate stage ST1 and the −Y side area of theupper surface of the measurement stage ST2 are proximate to or incontact with one another. In the present embodiment, because theoverhanging portion H1 is provided on the +Y side of the substrate stageST1 and the recessed portion 54 is provided on the −Y side of themeasurement stage ST2, the area of the upper surface of the substratestage ST1 in the vicinity of the overhanging portion H1 and the area ofthe upper surface of the measurement stage ST2 in the vicinity of therecessed portion 54 are proximate to or in contact with one another.Furthermore, the recovery ports 51 are provided in the vicinity of thearea where the upper surfaces of the measurement stage ST2 and thesubstrate stage ST1 are proximate to or in contact with one another;specifically, the recovery ports 51 are provided to the inner side ofthe recessed portion 54.

Here, the “proximate state” between the substrate stage ST1 and themeasurement stage ST2 means the state when the liquid immersion regionLR has moved between the upper surface F1 of the substrate stage ST1 andthe upper surface F2 of the measurement stage ST2, and the substratestage ST1 and the measurement stage ST2 have approached one another tothe extent that the liquid LQ does not leak out from between them;furthermore, the permissible value of the spacing between both stagesST1, ST2 differs depending on, for example, the material properties andthe surface treatment of both stages, and the type of the liquid LQ.

The illumination optical system IL comprises: an exposure light source;an optical integrator that uniformizes the luminous flux intensity ofthe light beam emitted from the exposure light source; a condenser lensthat condenses the exposure light EL from the optical integrator; arelay lens system; and a field stop that sets an illumination region onthe mask M illuminated by the exposure light EL. The illuminationoptical system IL illuminates the prescribed illumination region on themask M with the exposure light EL, which has a uniform luminous fluxintensity distribution. Examples of light that can be used as theexposure light EL emitted from the illumination optical system ILinclude: deep ultraviolet (DUV) light such as the bright lines (g-rays,h-rays, and i-rays) emitted from a mercury lamp and the like, and KrFexcimer laser light (248 nm wavelength); and vacuum ultraviolet (VUV)light such as ArF excimer laser light (193 nm wavelength) and F₂ laserlight (157 nm wavelength). ArF excimer laser light is used in thepresent embodiment.

In the present embodiment, pure water (purified water) is used as theliquid LQ. Pure water is capable of transmitting not only ArF excimerlaser light, but also DUV light such as the bright lines (g-rays,h-rays, and i-rays) emitted from a mercury lamp and the like, and KrFexcimer laser light (248 nm wavelength).

The movable mask stage MST holds the mask M. The mask stage MST holdsthe mask M via vacuum chucking (or electrostatic chucking). The maskstage MST, in a state wherein it is holding the mask M, is movable intwo dimensions within a plane perpendicular to the optical axis AX ofthe projection optical system PL, i.e., within the XY plane, and isfinely rotatable in the θZ directions by the drive of a drive mechanismMD, which includes a linear motor that is controlled by the controlapparatus CONT. Movable mirrors 31 are provided on the mask stage MST.In addition, a laser interferometer 32 is provided at a positionopposing each movable mirror 31. The laser interferometers 32 measure inreal time the position in the two dimensional directions, as well as therotational angle in the θZ directions (depending on the case, includingthe rotational angles in the θX and θY directions) of the mask M on themask stage MST. The measurement results of the laser interferometers 32are outputted to the control apparatus CONT. Based on the measurementresults of the laser interferometers 32, the control apparatus CONTcontrols the position of the mask M, which is held on the mask stageMST, by driving the drive mechanism MD.

The projection optical system PL, which projects the pattern of the maskM onto the substrate P at a prescribed projection magnification β,comprises a plurality of optical elements that are held by a lens barrelPK. In the present embodiment, the projection optical system PL is areduction system that has a projection magnification P of, for example,¼, ⅕, or ⅛. Furthermore, the projection optical system PL may also be aunity magnification system or an enlargement system. In addition, theprojection optical system PL may be: a dioptric system that does notinclude reflecting optical elements; a catoptric system that does notinclude refracting optical elements; or a catadioptric system thatincludes both reflecting optical elements and refracting opticalelements. Among the plurality of optical elements that constitute theprojection optical system PL, the first optical element LS1, which isthe closest to the image plane of the projection optical system PL,protrudes from the lens barrel PK.

The substrate stage ST1 comprises a substrate holder PH, which holds thesubstrate P, and a plate member T that is held by the substrate holderPH, which is movable on the image plane side of the projection opticalsystem PL. The substrate holder PH holds the substrate P via, forexample, vacuum chucking. The substrate stage ST1, in a state wherein itis holding the substrate P via the substrate holder PH, is movable intwo dimensions within the XY plane that is substantially parallel to theimage plane of the projection optical system PL on the image plane sideof the projection optical system PL, and can be finely rotated in the θZdirections by the drive of the drive mechanism SD, which includes alinear motor that is controlled by the control apparatus CONT.Furthermore, the substrate stage ST1 is also movable in the Z axialdirections and the θX and θY directions. Accordingly, the upper surfaceof the substrate P held by the substrate stage ST1 is movable in thedirections of six degrees of freedom, i.e., the X, Y, and Z axialdirections and the θX, θY, and θZ directions. Movable mirrors 33 areeach provided to a side surface of the substrate stage ST1. In addition,a laser interferometer 34 is provided at a position opposing eachmovable mirror 33. The laser interferometers 34 measure in real time theposition in the two dimensional directions as well as the rotationalangle of the substrate P on the substrate stage ST1. In addition, theexposure apparatus EX comprises an oblique incidence type focus levelingdetection system (not shown) that detects surface position informationof the upper surface of the substrate P that is supported by thesubstrate stage ST1 as disclosed in, for example, Japanese UnexaminedPatent Application, Publication No. H08-37149. The focus levelingdetection system detects the surface position information (positionalinformation in the Z axial directions, and inclination information inthe θX and θY directions of the substrate P) of the upper surface of thesubstrate P. Furthermore, the focus leveling detection system may alsoemploy a system that uses an electrostatic capacitance type sensor. Themeasurement results of the laser interferometers 34 are output to thecontrol apparatus CONT. The detection results of the focus levelingdetection system are also output to the control apparatus CONT. Based onthe detection results of the focus leveling detection system, thecontrol apparatus CONT aligns the upper surface of the substrate P withthe image plane of the projection optical system PL by driving the drivemechanism SD and controlling the focus position (Z position) andinclination angle (θX and θY) of the substrate P; in addition, based onthe measurement results of the laser interferometers 34, the controlapparatus CONT controls the position of the substrate P in the X and Yaxial directions and the θZ directions.

The measurement stage ST2 mounts various measuring instruments(including a measuring member) that perform measurements related to theexposure process, and is movable on the image plane side of theprojection optical system PL. Examples of such measuring instrumentsinclude: a fiducial mark plate whereon a plurality of fiducial(reference) marks are formed as disclosed in, for example, JapaneseUnexamined Patent Application, Publication No. H5-21314; a nonuniformitysensor for measuring the luminous flux intensity nonuniformity asdisclosed in, for example, Japanese Unexamined Patent Application,Publication No. S57-117238 and for measuring the amount of fluctuationsin the transmittance of a projection optical system PL for exposurelight EL as disclosed in Japanese Unexamined Patent Application,Publication No. 2001-267239; an aerial image measuring sensor asdisclosed in Japanese Unexamined Patent Application, Publication No.2002-14005; and an irradiance sensor (luminous flux intensity sensor) asdisclosed in Japanese Unexamined Patent Application, Publication No.H11-16816. Like the upper surface F1 of the substrate stage ST1, theupper surface F2 of the measurement stage ST2 is a flat surface (flatportion).

In the present embodiment, to perform immersion exposure, in which thesubstrate P is exposed with the exposure light EL through the projectionoptical system PL and the liquid LQ, the abovementioned nonuniformitysensor, aerial image measuring sensor, and irradiance sensor, which areemployed in measurements that use the exposure light EL, receive theexposure light EL through the projection optical system PL and theliquid LQ. Furthermore, for example, one part of the optical system ofeach sensor may be mounted on the measurement stage ST2, or the entiresensor may be disposed thereon.

In a state wherein the measuring instruments are mounted, themeasurement stage ST2 can be moved in two dimensions within the XY planethat is substantially parallel to the image plane of the projectionoptical system PL on the image plane side thereof, and can be finelyrotated in the θZ directions by the drive of the drive mechanism SD,which includes a linear motor that is controlled by the controlapparatus CONT. Furthermore, the measurement stage ST2 is also movablein the Z axial directions and the θX and θY directions. Namely, like thesubstrate stage ST1, the measurement stage ST2 is movable in thedirections of six degrees of freedom, i.e., the X, Y, and Z axialdirections and the θX, θY, and θZ directions. Movable mirrors 37 areeach provided to a side surface of the measurement stage ST2. Inaddition, a laser interferometer 38 is provided at a position opposingeach movable mirror 37. The laser interferometers 38 measure in realtime the position in the two dimensional directions and the rotationalangle of the measurement stage ST2.

An off axis alignment system ALG, which detects alignment marks on thesubstrate P and fiducial marks on the fiducial mark plate, is providedin the vicinity of the tip of the projection optical system PL. With thealignment system ALG of the present embodiment, a FIA (Field ImageAlignment) system of the type disclosed in, for example, JapaneseUnexamined Patent Application, Publication No. H4-65603 is employedthat: irradiates a target mark on the substrate P with a broadbanddetection light beam that does not photosensitize the photosensitivematerial on the substrate P; uses an imaging device (e.g., a CCD) tocapture an image of an index (an index pattern on an index plateprovided in the alignment system ALG), which is not shown, and an imageof the target mark that is imaged on a light receiving surface by thelight reflected from that target mark; and measures the position of themark by image processing these imaging signals.

In addition, two mask alignment systems RAa, RAb, each of whichcomprises a TTR type alignment system, are provided in the vicinity ofthe mask stage MST spaced apart in the Y axial directions by aprescribed spacing, wherein light of the exposure light wavelength isused to simultaneously observe an alignment mark on the mask M and acorresponding fiducial mark on the fiducial mark plate through theprojection optical system PL. The mask alignment system of the presentembodiment employs a VRA (Visual Reticle Alignment) system that detectsthe position of a mark by irradiating the mark with light and imageprocessing the image data of the mark imaged by, for example, a CCDcamera, as disclosed in, for example, Japanese Unexamined PatentApplication, Publication No. H7-176468.

The liquid supply mechanism 10 and the liquid recovery mechanism 20 ofthe liquid immersion mechanism 1 will now be explained. The liquidsupply mechanism 10 supplies the liquid LQ to the image plane side ofthe projection optical system PL and comprises a liquid supply section11, which is capable of feeding the liquid LQ, as well as a supply pipe13, which has one end portion that is connected to the liquid supplysection 11. The other end portion of the supply pipe 13 is connected tothe nozzle member 70. An internal passageway (supply passageway) thatconnects the supply ports 12 and the other end portion of the supplypipe 13 is formed inside the nozzle member 70. The liquid supply section11 comprises, for example, a tank that stores the liquid LQ, a pressurepump, and a filter unit that removes foreign matter from the liquid LQ.The control apparatus CONT controls the liquid supply operation of theliquid supply section 11. Furthermore, the tank, the pressure pump, andthe filter unit do not all need to be provided to the liquid supplymechanism 10 of the exposure apparatus EX, and at least one of them canbe substituted with equipment at, for example, the plant where theexposure apparatus EX is installed.

The liquid recovery mechanism 20 recovers the liquid LQ on the imageplane side of the projection optical system PL and comprises: a liquidrecovery section 21 that is capable of recovering the liquid LQ; and arecovery pipe 23, one end portion of which is connected to the liquidrecovery section 21. The other end portion of the recovery pipe 23 isconnected to the nozzle member 70. An internal passageway (recoverypassageway) that connects the recovery ports 22 with the other endportion of the recovery pipe 23 is formed inside the nozzle member 70.The liquid recovery section 21 is provided with, for example: a vacuumsystem (a suction apparatus) such as a vacuum pump; a gas-liquidseparator that separates the recovered liquid LQ and gas; and a tankthat stores the recovered liquid LQ. Furthermore, the tank, the vacuumsystem, and the gas-liquid separator do not all need to be provided tothe liquid recovery mechanism 20 of the exposure apparatus EX, and atleast one of them can be substituted with equipment at, for example, theplant where the exposure apparatus EX is installed.

The supply ports 12, which supply the liquid LQ, and the recovery ports22, which recover the liquid LQ, are formed in a lower surface 70A ofthe nozzle member 70. The lower surface 70A of the nozzle member 70 isprovided at a position that opposes the upper surface of the substrate Pand the upper surfaces F1, F2 of the stages ST1, ST2. The nozzle member70 is an annular member that is provided so that it surrounds a sidesurface of the first optical element LS1, and a plurality of the supplyports 12 are provided in the lower surface 70A of the nozzle member 70so that it surrounds the first optical element LS1 of the projectionoptical system PL (the optical axis AX of the projection optical systemPL). In addition, the recovery ports 22 are provided in the lowersurface 70A of the nozzle member 70 spaced apart from the outer side ofthe supply ports 12 with respect to the first optical element LS1, andare provided so that they surround the first optical element LS1 and thesupply ports 12.

Furthermore, the control apparatus CONT locally forms the liquidimmersion region LR of the liquid LQ on the substrate P by using theliquid supply mechanism 10 to supply a prescribed amount of the liquidLQ onto the substrate P, and by using the liquid recovery mechanism 20to recover a prescribed amount of the liquid LQ on the substrate P. Whenforming the liquid immersion region LR of the liquid LQ, the controlapparatus CONT drives the liquid supply section 11 and the liquidrecovery section 21. When the liquid LQ is sent from the liquid supplysection 11 under the control of the control apparatus CONT, the liquidLQ sent from the liquid supply section 11 flows through the supply pipe13 and then is supplied through the supply passageway of the nozzlemember 70 to the image plane side of the projection optical system PLfrom the supply ports 12. In addition, when the liquid recovery section21 is driven under the control of the control apparatus CONT, the liquidLQ on the image plane side of the projection optical system PL flowsinto the recovery passageway of the nozzle member 70 through therecovery ports 22, flows through the recovery pipe 23, and is thencollected by the liquid recovery section 21.

The following explains the substrate stage ST1 (substrate holder PH),referencing FIG. 2 and FIG. 3. FIG. 2 is a side cross sectional view ofthe substrate holder PH in a state wherein the substrate P and the platemember T are vacuum chucked, and FIG. 3 is a plan view of the substratestage ST1 viewed from above.

In FIG. 2, the substrate holder PH comprises a base material PHB, afirst holding portion PH1, which is formed in the base material PHB andvacuum chucks the substrate P, and a second holding portion PH2, whichis formed in the base material PHB and detachably holds the plate memberT, wherein an upper surface Ta is formed that is substantially flushwith an upper surface Pa of the substrate P, at the circumference of thesubstrate P held by the first holding portion PH1. The plate member T isdifferent from the base material PHB, and is provided so that it can bedetached (i.e., it is replaceable) from the base material PHB of thesubstrate holder PH. In addition, as shown in FIG. 3, the plate member Tis a substantially annular member, and a substantially circular hole TH,wherein the substrate P can be disposed, is formed at the center portionthereof. Furthermore, the plate member T held by the second holdingportion PH2 is disposed so that it surrounds the circumference of thesubstrate P that is held by the first holding portion PH1. In thepresent embodiment, the substrate stage ST1 refers to the state whereinthe plate member T is vacuum chucked to the base material PHB.

The plate member T is liquid repellent with respect to the liquid LQ.The plate member T is made of a liquid repellent material, for example,a fluororesin such as polytetrafluoroethylene (Teflon™), or an acrylicresin. Furthermore, the plate member T may be made of, for example, ametal and its surface may be coated with a liquid repellent materialsuch as a fluororesin.

In FIG. 2, the upper surface Ta and a lower surface Tb of the platemember T are each a flat surface (flat portion). In addition, the platemember T has substantially the same thickness as the substrate P.Furthermore, the upper surface (flat surface) Ta of the plate member Tthat is held by the second holding portion PH2 is substantially flushwith the upper surface Pa of the substrate P that is held by the firstholding portion PH1. Namely, at the circumference of the substrate Pthat is held by the first holding portion PH1, the plate member T thatis held by the second holding portion PH2 forms the flat surface Ta,which is substantially flush with the upper surface Pa of that substrateP. In the present embodiment, the upper surface of the substrate stageST1 is formed so that, when the substrate P is held thereon, thesubstantially entire area of that upper surface of the substrate stageST1, including the upper surface Pa of the held substrate P, forms aflat surface (full flat surface).

The external form of the plate member T is rectangular in a plan view,and is formed so that it is larger than the external form of the basematerial PHB. Namely, a peripheral edge portion of the plate member Tthat is held by the second holding portion PH2 forms the overhangingportion (protruding portion) H1, which projects from the side surface tothe outer side of the base material PHB. The area of the overhangingportion H1 on the +Y side forms a protruding portion that projectstoward the measurement stage ST2. In the present embodiment, the uppersurface Ta of the plate member T, which includes the upper surface ofthe overhanging portion H1, forms the upper surface F1 of the substratestage ST1. Furthermore, the area of the upper surface F1 of thesubstrate stage ST1 on the +Y side, i.e., the +Y side upper surface F1(Ta) of the overhanging portion H1, and the area of the upper surface F2of the measurement stage ST2 on the −Y side are proximate to or incontact with one another.

In the present embodiment, the movable mirrors 33 are provided in anarea below the overhanging portion H1. Thereby, even if the liquid LQflows out from the upper surface F1 (Ta), the overhanging portion H1 canprevent the liquid LQ from adhering to the movable mirrors 33.

As shown in FIG. 2 and FIG. 3, the first holding portion PH1 of thesubstrate holder PH comprises protruding first support portions 46,which are formed on the base material PHB, and an annular firstcircumferential wall portion 42, which is formed on the base materialPHB so that it surrounds the first support portions 46. The firstsupport portions 46 support a lower surface Pb of the substrate P, and aplurality of first support portions 46 are uniformly formed on the innerside of the first circumferential wall portion 42. In the presentembodiment, the first support portions 46 comprise a plurality ofsupport pins. In accordance with the shape of the substrate P, the firstcircumferential wall portion 42 is formed substantially annular in aplan view, and an upper surface 42A of the first circumferential wallportion 42 is formed so that it opposes a circumferential edge area(edge area) of the lower surface Pb of the substrate P. A first space131, which is surrounded by the base material PHB, the firstcircumferential wall portion 42, and the lower surface Pb of thesubstrate P, is formed on the lower surface Pb side of the substrate Pheld by the first holding portion PH1.

First suction ports 41 are formed on the base material PHB on the innerside of the first circumferential wall portion 42. The first suctionports 41 are for vacuum chucking the substrate P, and a plurality offirst suction ports 41 are provided at prescribed positions on the uppersurface of the base material PHB, excluding the areas where the firstsupport portions 46 are provided, on the inner side of the firstcircumferential wall portion 42. In the present embodiment, theplurality of first suction ports 41 are uniformly disposed on the innerside of the first circumferential wall portion 42. Each first suctionport 41 is connected to a first vacuum system 40 through a passageway45. The first vacuum system 40 is for negatively pressurizing the firstspace 131, which is surrounded by the base material PHB, the firstcircumferential wall portion 42, and the lower surface Pb of thesubstrate P, and includes a vacuum pump. As discussed above, the firstsupport portions 46 comprise support pins, and the first holding portionPH1 according to the present embodiment constitutes one part of aso-called pin chuck mechanism. The first circumferential wall portion 42functions as an outer wall portion that surrounds the outer side of thefirst space 131, which includes the first support portions 46, and thecontrol apparatus CONT vacuum chucks the substrate P to the firstsupport portions 46 by driving the first vacuum system 40 so that itsuctions gas (air) out of the interior of the first space 131 that issurrounded by the base material PHB, the first circumferential wallportion 42, and the substrate P, thereby negatively pressurizing thefirst space 131.

The second holding portion PH2 of the substrate holder PH comprises asubstantially annular second circumferential wall portion 62, which isformed on the base material PHB so that it surrounds the firstcircumferential wall portion 42 of the first holding portion PH1, anannular third circumferential wall portion 63, which is provided on theouter side of the second circumferential wall portion 62 and is formedon the base material PHB so that it surrounds the second circumferentialwall portion 62, and protruding second support portions 66, which areformed on the base material PHB between the second circumferential wallportion 62 and the third circumferential wall portion 63. The secondsupport portions 66 support the lower surface Tb of the plate member T,and a plurality of second support portions 66 are uniformly formedbetween the second circumferential wall portion 62 and the thirdcircumferential wall portion 63. Like the first support portions 46, thesecond support portions 66 in the present embodiment comprise aplurality of support pins. The second circumferential wall portion 62 isprovided on the outer side of the first circumferential wall portion 42with respect to the first space 131, and the third circumferential wallportion 63 is provided farther on the outer side of the secondcircumferential wall portion 62 with respect to the first space 131. Inaddition, the second circumferential wall portion 62 is formed inaccordance with the shape of the hole TH of the plate member T so thatit is substantially annular in a plan view. The third circumferentialwall portion 63 is formed substantially rectangular in a plan view onthe inner side of an edge portion on the outer side of the plate memberT. An upper surface 62A of the second circumferential wall portion 62 isformed so that it opposes an inner edge area (an inner side edge area)of the lower surface Tb of the plate member T in the vicinity of thehole TH. An upper surface 63A of the third circumferential wall portion63 is formed so that it opposes an area of the lower surface Tb of theplate member T that is slightly on the inner side of the outer edge area(the outer side edge area). A second space 132, which is surrounded bythe base material PHB, the second and third circumferential wallportions 62, 63, and the lower surface Tb of the plate member T, isformed on the lower surface Tb side of the plate member T held by thesecond holding portion PH2.

Second suction ports 61 are formed on the base material PHB between thesecond circumferential wall portion 62 and the third circumferentialwall portion 63. The second suction ports 61 are for vacuum chucking theplate member T, and a plurality of the second suction ports 61 areprovided between the second circumferential wall portion 62 and thethird circumferential wall portion 63 at prescribed positions on theupper surface of the base material PHB, excluding the areas of thesecond support portions 66. In the present embodiment, the plurality ofsecond suction ports 61 are uniformly disposed between the secondcircumferential wall portion 62 and the third circumferential wallportion 63.

Each of the second suction ports 61 is connected to a second vacuumsystem 60 through a passageway 65. The second vacuum system 60 is fornegatively pressurizing the second space 132, which is surrounded by thebase material PHB, the second and third circumferential wall portions62, 63, and the lower surface Tb of the plate member T, and includes avacuum pump. As discussed above, the second support portions 66 comprisesupport pins, and, like the first holding portion PH1, the secondholding portion PH2 according to the present embodiment constitutes onepart of the so-called pin chuck mechanism. The second and thirdcircumferential wall portions 62, 63 function as outer wall portionsthat enclose the outer sides of the second space 132, which includes thesecond support portions 66, and the control apparatus CONT vacuum chucksthe plate member T to the second support portions 66 by driving thesecond vacuum system 60 so as to suction the gas (air) out of theinterior of the second space 132 that is surrounded by the base materialPHB, the second and third circumferential wall portions 62, 63, and theplate member T, thereby negatively pressurizing the second space 132.

Furthermore, although a pin chuck mechanism is employed when vacuumchucking the substrate P in the present embodiment, other chuckmechanisms may be employed. Likewise, although a pin chuck mechanism isemployed when vacuum chucking the plate member T, other chuck mechanismsmay be employed. In addition, although vacuum chuck mechanisms areemployed when vacuum chucking the substrate P and the plate member T inthe present embodiment, at least one of them may use another mechanismsuch as an electrostatic chuck mechanism.

The first vacuum system 40 that negatively pressurizes the first space131 and the second vacuum system 60 that negatively pressurizes thesecond space 132 are mutually independent. The control apparatus CONTcan separately control the operation of the first vacuum system 40 andthe second vacuum system 60, and the operation of suctioning the firstspace 131 by the first vacuum system 40 and the operation of suctioningthe second space 132 by the second vacuum system 60 can be performedindependently. In addition, the control apparatus CONT controls thefirst vacuum system 40 and the second vacuum system 60, and can make thepressure of the first space 131 and the pressure of the second space 132different from one another.

As shown in FIG. 2 and FIG. 3, a gap A of approximately 0.1-1.0 mm isformed between the edge portion on the outer side of the substrate Pheld by the first holding portion PH1 and the edge portion on the innerside (hole TH side) of the plate member T provided at the circumferenceof the substrate P. In the present embodiment, the gap A isapproximately 0.3 mm. In addition, as shown in FIG. 3, a notched portionNT, which is a notch for alignment, is formed in the substrate P in thepresent embodiment. The shape of the plate member T is set in accordancewith the external form (shape of the notched portion NT) of thesubstrate P so that the gap in the notched portion NT between thesubstrate P and the plate member T is also approximately 0.1 to 1.0 mm.Specifically, a projection portion 150 that projects toward the innerside of the hole TH is provided to the plate member T so that itcorresponds to the shape of the notched portion NT of the substrate P.Thereby, the gap A of approximately 0.1 to 1.0 mm is secured between theplate member T and the entire area of the edge portion of the substrateP, which includes the notched portion NT. In addition, a protrudingportion 62N that corresponds to the shape of the projection portion 150of the plate member T is formed in the second circumferential wallportion 62 of the second holding portion PH2 and its upper surface 62A.In addition, a recessed portion 42N that corresponds to the shape of theprotruding portion 62N of the second circumferential wall portion 62 andthe notched portion NT of the substrate P is formed in the firstcircumferential wall portion 42 of the first holding portion PH1 and itsupper surface 42A. The recessed portion 42N of the first circumferentialwall portion 42 is provided at a position that opposes the protrudingportion 62N of the second circumferential wall portion 62, and aprescribed gap is formed between the recessed portion 42N and theprotruding portion 62N.

Furthermore, although the above explained an example of using thenotched portion NT as the notch of the substrate P, the prescribed gap Abetween the substrate P and the plate member T that surrounds such maybe secured in cases such as when there is no notch, or when anorientation flat portion is formed in the substrate P as the notch byshaping the plate member T, the first circumferential wall portion 42,and the second circumferential wall portion 62 in accordance with theexternal form of the substrate P.

The following explains the measurement stage ST2, referencing FIG. 4 andFIG. 5. As discussed above, the measurement stage ST2 mounts themeasuring instruments that perform measurements related to the exposureprocess, and its upper surface F2 forms a flat surface. In FIG. 5, afiducial mark plate FM wherein a plurality of fiducial marks are formed,a nonuniformity sensor 300, and an aerial image measuring sensor 400 areschematically shown as examples of measuring instruments (measuringmembers).

The measurement stage ST2 comprises a recovery mechanism 50 that iscapable of recovering the liquid LQ. The recovery mechanism 50 comprisesthe recovery ports 51, which are provided to the measurement stage ST2and are capable of recovering the liquid LQ, and a passageway 52, whichis connected to those recovery ports 51 and to a vacuum system 53.Furthermore, a gas-liquid separator (not shown) that separates gas fromthe recovered liquid LQ is provided along the passageway 52 between therecovery ports 51 and the vacuum system 53. The recovery mechanism 50 iscapable of recovering the liquid LQ through the recovery ports 51 by thedrive of the vacuum system 53. The liquid LQ recovered by the recoveryports 51 flows through the passageway 52 and then is stored in a tank(not shown).

The measurement stage ST2 comprises a recessed portion 54 thatcorresponds to the overhanging portion H1 of the substrate stage ST1.The recessed portion 54 is formed in an area (−Y side area) of the uppersurface of the measurement stage ST2 that is proximate to or in contactwith the substrate stage ST1, and is formed as a notch in one part ofthe upper surface F2 of the measurement stage ST2 on the −Y side.Furthermore, a groove portion 55, which extends in the X axialdirections, is formed on the inner side of the recessed portion 54 ofthe measurement stage ST2. The recovery ports 51 are provided in thegroove portion 55 formed in the recessed portion 54. As shown in FIG. 5,the recovery ports 51 are substantially circular in a plan view, and aplurality thereof are provided lined up in the X axial directions in abottom surface 55B of the groove portion 55. Furthermore, each of theplurality of recovery ports 51 is connected to the vacuum system 53through the passageway 52. Here, the bottom surface 55B of the grooveportion 55 is a flat surface that faces the +Z side.

The recessed portion 54 (groove portion 55) is formed in the area (−Yside area) of the upper surface of the measurement stage ST2 that isproximate to or in contact with the substrate stage ST1, and thereforethe recovery ports 51, which are formed on the inner side of thatrecessed portion 54 (groove portion 55), are provided in the vicinity ofthe area of the measurement stage ST2 that is proximate to or in contactwith the substrate stage ST1.

An area of the upper surface F2 of the measurement stage ST2 that isproximate to or in contact with the overhanging portion H1 of thesubstrate stage ST1 (plate member T) is formed by a liquid repellentmember 56. The liquid repellent member 56 may be made of a material, forexample a fluororesin such as polytetrafluoroethylene (Teflon™), or anacrylic resin, that is liquid repellent with respect to the liquid LQ.In addition, the liquid repellent member 56 also forms a wall surfacethat faces the −Y side of the inner edge area of the recessed portion54. The liquid repellent member 56 is detachable from the measurementstage ST2 (i.e., it is replaceable).

FIG. 6 is a plan view of the substrate stage ST1 and the measurementstage ST2, viewed from above. In FIG. 6, the drive mechanism SDcomprises linear motors 80, 81, 82, 83, 84, 85 for driving the substratestage ST1 and the measurement stage ST2. The drive mechanism SDcomprises a pair of Y axis linear guides 91, 93 that each extend in theY axial directions. The Y axis linear guides 91, 93 are disposed spacedapart by a prescribed spacing in the X axial directions. Each of the Yaxis linear guides 91, 93 comprises a magnet unit with a built-inpermanent magnet group that consists of multiple sets of north polemagnets and south pole magnets that are disposed alternately and atprescribed intervals along, for example, the Y axial directions.Moreover, two sliders 90, 94 are supported on the Y axis linear guide 91so that they are movable in the Y axial directions in a noncontactualstate. Likewise, two sliders 92, 95 are supported on the other Y axislinear guide 93 so that they are movable in the Y axial directions in anoncontactual state. Each of the sliders 90, 92, 94, 95 comprises a coilunit with built-in armature coils disposed at prescribed intervalsalong, for example, the Y axis. Namely, in the present embodiment, thesliders 90, 94, which each comprise a coil unit, and the Y axis linearguide 91, which comprises a magnet unit, constitute the moving coil typeY axis linear motors 82, 84. Likewise, the sliders 92, 95 and the Y axislinear guide 93 constitute the moving coil type Y axis linear motors 83,85.

One end portion and the other end portion of each of the sliders 90, 92,which constitute the Y axis linear motors 82, 83, are fixed in thelongitudinal direction of an X axis linear guide 87, which extends inthe X axial directions. In addition, one end portion and the other endportion of each of the sliders 94, 95, which constitute the Y axislinear motors 84, 85, are fixed in the longitudinal direction of an Xaxis linear guide 89, which extends in the X axial directions.Accordingly, the X axis linear guide 87 is movable in the Y axialdirections by the Y axis linear motors 82, 83, and the X axis linearguide 89 is movable in the Y axial directions by the Y axis linearmotors 84, 85.

The X axis linear guides 87, 89 each comprise a coil unit that hasbuilt-in armature coils, which, for example, are disposed at prescribedintervals along the X axial directions. The X axis linear guide 89 isprovided in a state wherein it is inserted in an opening that is formedin the substrate stage ST1. A magnet unit 88, which comprises apermanent magnet group that consists of multiple sets of north polemagnets and south pole magnets disposed alternately and at prescribedintervals along, for example, the X axial directions, is provided in theinner portion of the opening of the substrate stage ST1. The magnet unit88 and the X axis linear guide 89 constitute the moving magnet type Xaxis linear motor 81 that drives the substrate stage ST1 in the X axialdirections. Likewise, the X axis linear guide 87 is provided in a statewherein it is inserted in an opening formed in the measurement stageST2. A magnet unit 86 is provided the opening of the measurement stageST2. The magnet unit 86 and the X axis linear guide 87 constitute themoving magnet type X axis linear motor 80 that drives the measurementstage ST2 in the X axial directions.

Furthermore, making the thrust generated by each of the two Y axislinear motors 84, 85 (or 82, 83) slightly different makes it possible tocontrol the substrate stage ST1 (or the measurement stage ST2) in the θZdirections. In addition, the substrate stage ST1 and the measurementstage ST2 are each shown in the drawings as single stages, but they eachactually comprise an XY stage, which is driven by its respective Y axislinear motor, and a Z tilt stage, which is mounted to an upper portionof the XY stage via a Z leveling drive mechanism (e.g., a voice coilmotor) and is finely driven relative to the Z axial directions and theθX and θY directions with respect to the XY stage. Furthermore, thesubstrate holder PH (refer to FIG. 1), which holds the substrate P, issupported by the Z tilt stage.

The following explains a parallel process operation that uses thesubstrate stage ST1 and the measurement stage ST2, referencing FIG. 6through FIG. 8B.

As shown in FIG. 6, when performing immersion exposure of the substrateP, the control apparatus CONT makes the measurement stage ST2 stand byat a prescribed stand-by position where it will not collide with thesubstrate stage ST1. Furthermore, in a state wherein the substrate stageST1 and the measurement stage ST2 are spaced apart, the controlapparatus CONT performs a step-and-scan type immersion exposure of thesubstrate P, which is held by the substrate stage ST1. When performingthe immersion exposure of the substrate P, the control apparatus CONTuses the liquid immersion mechanism 1 to form the liquid immersionregion LR of the liquid LQ on the substrate stage ST1.

After completing the immersion exposure of the substrate P on thesubstrate stage ST1, the control apparatus CONT uses the drive mechanismSD to drive at least one of the substrate stage ST1 and the measurementstage ST2, and, as shown in FIG. 7A, causes the upper surface F2 of themeasurement stage ST2 to be in contact with (or proximate to) the uppersurface F1 of the substrate stage ST1. In greater detail, the linearedge of the upper surface F1 (plate member T) of the substrate stage ST1on the +Y side and the linear edge of the upper surface F2 (liquidrepellent member 56) of the measurement stage ST2 on the −Y side arecaused to be in contact with (or proximate to) one another.

Next, the control apparatus CONT uses the drive mechanism SD tosimultaneously move the substrate stage ST1 and the measurement stageST2 in the −Y direction, while maintaining the relative positionalrelationship of the substrate stage ST1 and the measurement stage ST2 inthe Y axial directions. Namely, while maintaining a prescribed statewherein the upper surface F1 of the substrate stage ST1 and the uppersurface F2 of the measurement stage ST2 contact (or are proximate to)one another, the control apparatus CONT moves them together in the −Ydirection within a prescribed area that includes a position that isdirectly below the projection optical system PL.

By moving the substrate stage ST1 and the measurement stage ST2together, the control apparatus CONT moves the liquid LQ, which isretained between the substrate P and the first optical element LS1 ofthe projection optical system PL, from the upper surface F1 of thesubstrate stage ST1 to the upper surface F2 of the measurement stageST2. With the movement of the substrate stage ST1 and the measurementstage ST2 in the −Y direction, the liquid immersion region LR of theliquid LQ, which is formed between the substrate P and the first opticalelement LS1 of the projection optical system PL, moves to the uppersurface of the substrate P, the upper surface F1 of the substrate stageST1, and the upper surface F2 of the measurement stage ST2, in thatorder. Furthermore, along the way of moving from the upper surface F1 ofthe substrate stage ST1 to the upper surface F2 of the measurement stageST2, the liquid immersion region LR of the liquid LQ spans the uppersurface F1 of the substrate stage ST1 and the upper surface F2 of themeasurement stage ST2, as shown in FIG. 7B.

When the substrate stage ST1 and the measurement stage ST2 further movetogether a prescribed distance in the −Y direction from the state shownin FIG. 7B, they transition to a state wherein the liquid LQ is heldbetween the measurement stage ST2 and the first optical element LS1 ofthe projection optical system PL, as shown in FIG. 8A. Namely, theliquid immersion region LR of the liquid LQ is disposed on the uppersurface F2 of the measurement stage ST2.

Next, the control apparatus CONT uses the drive mechanism SD to move thesubstrate stage ST1 to a prescribed substrate exchange position andexchanges the substrate P. In addition, in parallel therewith,prescribed measurement processes that use the measurement stage ST2 areperformed as needed. An example of such a measurement process is thebaseline measurement of the alignment system ALG. Specifically, thecontrol apparatus CONT uses the mask alignment systems RAa, RAb, whichwere discussed above, to simultaneously detect a pair of first fiducialmarks on the fiducial mark plate FM that is provided on the measurementstage ST2 and corresponding mask alignment marks on the mask M, andthereby detects the positional relationship between the first fiducialmarks and the corresponding mask alignment marks. Simultaneoustherewith, by detecting a second fiducial mark on the fiducial markplate FM with the alignment system ALG, the control apparatus CONTdetects the positional relationship between the second fiducial mark anda detection reference position of the alignment system ALG. Furthermore,based on the positional relationship between the abovementioned firstfiducial marks and the corresponding mask alignment marks, thepositional relationship between the second fiducial mark and thedetection reference position of the alignment system ALG, and thealready known positional relationship between the first fiducial marksand the second fiducial mark, the control apparatus CONT derives thedistance (positional relationship) between the center of the projectionof the mask pattern projected by the projection optical system PL andthe detection reference position of the alignment system ALG, i.e., itderives baseline information of the alignment system ALG FIG. 8B showsthe state at this time.

Furthermore, the detection of the first fiducial marks by the maskalignment system and the detection of the second fiducial mark by thealignment system ALG do not necessarily need to be performedsimultaneously, and may be performed in a sequential time series; inaddition, the position of the measurement stage ST2 when detecting thefirst fiducial marks and the position of the measurement stage ST2 whendetecting the second fiducial mark may be different.

Furthermore, after completing the process discussed above on both stagesST1, ST2, the control apparatus CONT performs the alignment process onthe exchanged substrate P by, for example, causing the upper surface F2of the measurement stage ST2 and the upper surface F1 of the substratestage ST1 to be in contact with (or proximate to) one another and, in astate wherein that relative positional relationship is maintained, movesthem within the XY plane. Specifically, the control apparatus CONT usesthe alignment system ALG to detect the alignment marks on the exchangedsubstrate P and determines the positional coordinates (arraycoordinates) of each of the plurality of shot regions provided on thesubstrate P.

Subsequently, in the reverse sequence of that described earlier, thecontrol apparatus CONT moves both stages ST1, ST2 together in the +Ydirection while maintaining the relative positional relationship of thesubstrate stage ST1 and the measurement stage ST2 in the Y axialdirections, and, after moving the substrate stage ST1 (substrate P) tobelow the projection optical system PL, retracts the measurement stageST2 to a prescribed position. Thereby, the liquid immersion region LR isdisposed on the upper surface F1 of the substrate stage ST1. Also, whenmoving the liquid immersion region LR of the liquid LQ from the uppersurface F2 of the measurement stage ST2 to the upper surface F1 of thesubstrate stage ST1, the liquid immersion region LR spans the uppersurface F1 of the substrate stage ST1 and the upper surface F2 of themeasurement stage ST2.

Subsequently, the control apparatus CONT performs a step-and-scan typeimmersion exposure operation on the substrate P and sequentiallytransfers the pattern of the mask M to each of the plurality of shotregions on the substrate P. Furthermore, the alignment of each of theshot regions on the substrate P with the mask M is performed based onthe positional coordinates of the plurality of shot regions on thesubstrate P, which were obtained as a result of the substrate alignmentprocess discussed above, and the baseline information, which wasmeasured immediately beforehand.

Furthermore, the alignment process may be executed in a state whereinthe substrate stage ST1 and the measurement stage ST2 are spaced apart,or one part of the alignment process may be executed in a state whereinthe substrate stage ST1 and the measurement stage ST2 are spaced apartand the remaining part may be executed in a state wherein the substratestage ST1 and the measurement stage ST2 are in contact with (orproximate to) one another. In addition, the measurement operation is notlimited to the baseline measurement discussed above; for example, themeasurement stage ST2 may be used to perform, for example, luminous fluxintensity measurement, luminous flux intensity nonuniformitymeasurement, or aerial image measurement in parallel with, for example,substrate exchange, and the process of, for example, calibrating theprojection optical system PL may be performed based on those measurementresults, which are taken into account when subsequently exposing thesubstrate P.

In the present embodiment, after the exposure of one substrate P iscomplete, it is possible to start the next exposure of another substrateP without going through the process of recovering all of the liquid LQand then resupplying such, which makes it possible to improvethroughput. In addition, various measurement operations are performed atthe measurement stage ST2 during the substrate exchange operation withthe substrate stage ST1, and those measurement results can be taken intoaccount in the exposure operation of the subsequent substrate P, whichmakes it possible to perform highly accurate exposure operation withoutleading to a decline in throughput attendant with the measurementoperations. In addition, the liquid LQ is always present on the imageplane side of the projection optical system PL, which makes it possibleto effectively prevent the occurrence of adhered residue (a so-calledwatermark) of the liquid LQ.

FIG. 9 shows a state wherein the substrate stage ST1 and the measurementstage ST2 are moved together while maintaining a first state wherein theupper surface F1 of the substrate stage ST1 and the upper surface F2 ofthe measurement stage ST2 are proximate to (or in contact with) oneanother. When the substrate stage ST1 and the measurement stage ST2 arein the state (first state) shown in FIG. 9, the overhanging portion H1of the substrate stage ST1 is disposed over the recessed portion 54 ofthe measurement stage ST2. Thereby, in the first state, the recoveryports 51 provided on the inner side of the recessed portion 54transition to a state wherein they are closed by the overhanging portionH1. In addition, the vicinity of the areas wherein the upper surface F1of the substrate stage ST1 and the upper surface F2 of the measurementstage ST2 are mutually proximate to (or in contact with) one another areformed by the plate member T and the liquid repellent member 56,respectively, and are liquid repellent. Accordingly, even if the liquidLQ of the liquid immersion region LR is disposed on a gap G1 between theupper surface F1 of the substrate stage ST1 (plate member T) and theupper surface F2 of the measurement stage ST2 (liquid repellent member56), the surface tension of the liquid LQ can suppress the occurrence ofa problem wherein the liquid LQ leaks out through the gap G1.Furthermore, the plate member T and the liquid repellent member 56 arereplaceably provided, which makes it possible to provide the stages ST1,ST2 with a plate member T and a liquid repellent member 56 that are madeof a material that has physical properties that are optimal for the type(physical properties) of the liquid LQ used so that the liquid LQ doesnot leak out from the gap G1. In addition, if the liquid repellencyperformance of a member deteriorates, it can be replaced.

In addition, in the prescribed state wherein the upper surface F1 of thesubstrate stage ST1 and upper surface F2 of the measurement stage ST2are proximate to (or in contact with) one another, the upper surface F1of the substrate stage ST1 and the upper surface F2 of the measurementstage ST2 are substantially flush with one another, which makes itpossible to satisfactorily move the liquid immersion region LR of theliquid LQ between the upper surface F1 of the substrate stage ST1 andthe upper surface F2 of the measurement stage ST2.

Furthermore, by moving the substrate stage ST1 and the measurement stageST2 together in a state wherein the recovery ports 51 are closed by theoverhanging portion H1, the control apparatus CONT moves the liquidimmersion region LR between the upper surface F1 of the substrate stageST1 and the upper surface F2 of the measurement stage ST2 in a statewherein the liquid LQ is held between the projection optical system PLand at least one of the upper surface F1 of the substrate stage ST1 andthe upper surface F2 of the measurement stage ST2.

In addition, even if the liquid LQ leaks out of the gap G1 when theliquid immersion region LR is moved in the first state, the grooveportion 55 is provided on the lower side of the gap G1, and the liquidLQ that leaks out is consequently trapped by the groove portion 55.Accordingly, it is possible to prevent the occurrence of the problemwherein the liquid LQ flows out, for example, to the outer sides of thestages ST1, ST2 or onto the base member BP. In addition, because therecovery ports 51 of the recovery mechanism 50 are provided on the innerside of the groove portion 55, the liquid LQ that leaks out from the gapG1 can be recovered through the recovery ports 51.

FIG. 10 shows a state (second state) wherein the liquid LQ is beingrecovered through the recovery ports 51. For example, in cases when allof the liquid LQ of the liquid immersion region LR is recovered, such aswhen maintenance of the exposure apparatus EX is performed, the controlapparatus CONT sets the relative positional relationship between thesubstrate stage ST1 and the measurement stage ST2 to the second stateshown in FIG. 10, which is different from the first state. Namely, thecontrol apparatus CONT controls the drive of the drive mechanism SD toform a gap G2 between the upper surface F1 of the substrate stage ST1and the upper surface F2 of the measurement stage ST2, thereby exposingthe groove portion 55 and the recovery ports 51 provided on the innerside thereof. At this time, one part of the lower surface Tb of theoverhanging portion H1 (plate member T) is disposed so that it overlapsan upper surface 58 above the groove portion 55, which is an area of onepart of the recessed portion 54 of the measurement stage ST2. Aprescribed gap G3 is formed between the lower surface Tb of the platemember T and the upper surface 58. Furthermore, in the second statewherein the gap G2 is formed between the upper surface F1 of thesubstrate stage ST1 and the upper surface F2 of the measurement stageST2 and the recovery ports 51 are exposed, the liquid LQ is recovered bythe recovery ports 51 of the measurement stage ST2 while moving thesubstrate stage ST1 and the measurement stage ST2 together. By movingthe substrate stage ST1 and the measurement stage ST2 and disposing thegap G2 below the projection optical system PL, the liquid LQ held belowthe projection optical system PL flows into the groove portion 55through the gap G2 by the force of gravity, and is collected through therecovery ports 51. In addition, when the gap G2 is formed and the liquidLQ is being recovered, the prescribed gap G3 formed between the lowersurface Tb of the plate member T and the upper surface 58 makes itpossible to suppress the flow of the liquid LQ, which flowed in from thegap G2, out through the gap G3 by the surface tension of the liquid LQ.Furthermore, in the state shown in FIG. 10, the recovery mechanism 50may recover the liquid LQ in a state wherein the substrate stage ST1 andthe measurement stage ST2 are stopped.

In addition, control apparatus CONT performs the operation of recoveringthe liquid LQ via the recovery ports 51 provided to the measurementstage ST2 in parallel with the operation of recovering the liquid viathe recovery ports 22 of the nozzle member 70 of the liquid immersionmechanism 1. For example, when the liquid immersion region LR is on theupper surface F1 of the substrate stage ST1 or on the upper surface F2of the measurement stage ST2, the control apparatus CONT uses the drivemechanism SD to move the stages ST1, ST2 while recovering the liquid LQvia the recovery ports 22 of the nozzle member 70, and thereby moves theliquid immersion region LR to the gap G2. Furthermore, when the liquidLQ of the liquid immersion region LR begins to flow into the grooveportion 55 (or before it begins to flow in, or after a prescribed timehas elapsed since it began to flow in), the control apparatus CONTdrives the recovery mechanism 50 and starts the operation of recoveringthe liquid LQ via the recovery ports 51 that are provided to themeasurement stage ST2. At this time, the operation of recovering theliquid via the recovery ports 22 of the nozzle member 70 of the liquidimmersion mechanism 1 continues. The recovery ports 22 of the liquidimmersion mechanism 1 recover the liquid LQ from above the measurementstage ST2. The liquid LQ of the liquid immersion region LR flows intothe groove portion 55 by the force of gravity, and is recovered by therecovery ports 51 of the measurement stage ST2 and by the recovery ports22 of the liquid immersion mechanism 1, which are provided above themeasurement stage ST2.

As explained above, the recovery ports 51 that are provided to themeasurement stage ST2 can satisfactorily recover the liquid LQ.Providing the recovery ports 51 to the measurement stage ST2 disposed onthe image plane side of the projection optical system PL makes itpossible to rapidly and satisfactorily recover the liquid LQ by theforce of gravity. In addition, because the recovery ports 51 areprovided to the measurement stage ST2, it is possible to suppressadverse effects upon the substrate stage ST1 when recovering the liquidLQ.

In addition, according to the present embodiment, it is possible toswitch between one state, wherein the liquid immersion region LR movesbetween the upper surface F1 of the substrate stage ST1 and the uppersurface F2 of the measurement stage ST2, and another state, wherein theliquid LQ is recovered using the recovery ports 51, merely by changingthe relative positional relationship between the substrate stage ST1 andthe measurement stage ST2, and it is also possible, with a simpleconfiguration, to rapidly recover the liquid LQ while preventing it fromleaking out.

Second Embodiment

The following explains the second embodiment, referencing FIG. 11. Inthe explanation below, constituent parts that are identical orequivalent to those in the embodiments discussed above are assignedidentical symbols, and the explanations thereof are thereforeabbreviated or omitted.

The distinctive feature of the second embodiment is that a liquidrecovery member 57 is disposed on the inner side of the groove portion55. The liquid recovery member 57 is disposed on the recovery ports 51.The liquid recovery member 57 comprises a sponge member that consistsof, for example, a ceramic porous member or a synthetic resin. Theliquid LQ can be satisfactorily held by disposing the liquid recoverymember 57 in this manner. In addition, disposing the liquid recoverymember 57 in the groove portion 55 makes it possible to omit therecovery mechanism 50, which includes the recovery ports 51. Because theliquid LQ is held by the liquid recovery member 57 even if the recoverymechanism 50 is omitted, it is possible to prevent the problem whereinthe liquid LQ flows out, for example, onto the base member BP. Inaddition, making the liquid recovery member 57 replaceable makes itpossible to replace the one that holds the liquid LQ or a contaminatedone with a new one.

Third Embodiment

The following explains the third embodiment, referencing FIG. 12. Thedistinctive feature of the third embodiment is that the recovery ports51 are provided to the upper surface F2 of the measurement stage ST2.Namely, in the present embodiment, the recovery ports 51 are not formedon the inner side of the recessed portion 54. Furthermore, the recessedportion 54 that corresponds to the overhanging portion H1 of thesubstrate stage ST1 is formed on the −Y side area of the upper surfaceof the measurement stage ST2. Furthermore, in the third embodiment aswell, a plurality of the recovery ports 51 can be provided along the Xdirections.

When recovering the liquid LQ, the control apparatus CONT disposes theliquid immersion region LR on the upper surface F2 of the measurementstage ST2 and recovers the liquid LQ through the recovery ports 51 thatare formed in that upper surface F2. In the present embodiment, becausethe recovery ports 51 and the liquid LQ directly contact one another,the liquid LQ can be satisfactorily recovered. Furthermore, in the thirdembodiment, it is also possible to omit the overhanging portion(protruding portion) H1 of the substrate stage ST1 and the recessedportion 54 of the measurement stage ST2.

Fourth Embodiment

The following explains the fourth embodiment, referencing FIG. 13. Thedistinctive feature of the fourth embodiment is that a protrudingportion H1′, which projects from the substrate stage ST1 toward themeasurement stage ST2, is provided at substantially the center portionof the side surface of the substrate stage ST1 in the Z axialdirections. Namely, in the present embodiment, the protruding portionH1′ does not form the upper surface F1 of the substrate stage ST1. Inaddition, a recessed portion 54′ that corresponds to the protrudingportion H1′ is formed in the measurement stage ST2.

Fifth Embodiment

FIG. 14 shows the fifth embodiment. As shown in FIG. 14, the protrudingportion H1′ may be provided at substantially the center portion of theside surface of the measurement stage ST2 in the Z axial directions, andthe recessed portion 54′ may be provided in the substrate stage ST1.Furthermore, the groove portion 55 may be formed in the protrudingportion H1′ and the recovery ports 51 may be provided on the inner sideof that groove portion 55. In addition, in the present embodiment, whenmoving the liquid immersion region LR between the upper surface F1 ofthe substrate stage ST1 and the upper surface F2 of the measurementstage ST2, the substrate stage ST1 and the measurement stage ST2 mayapproach one another and the protruding portion H1′ may be disposed onthe inner side of the recessed portion 54′.

Furthermore, in the second through fifth embodiments discussed above, itis also possible to jointly use the recovery ports 22 of the liquidimmersion mechanism 1 when recovering all of the liquid LQ.

In addition, in the first and second embodiments discussed above, thegroove portion 55 of the measurement stage ST2 is continuously formedfrom one end to the other end of the measurement stage ST2 in the Xaxial directions, but may be provided at just one part in the X axialdirections, or may be discontinuously formed.

In addition, in the first and fifth embodiments discussed above, therecovery ports 51 are disposed in the bottom surface of the grooveportion 55, but, instead of forming the recovery ports, at least onethin tube that has micropores that form the recovery ports may bedisposed inside the groove portion 55. In this case, the thin tubeitself constitutes one part of the passageway 52.

In addition, in the first, second and fifth embodiments discussed above,the bottom surface of the groove portion 55 is a flat surface, but itmay be inclined with respect to the XY plane. In this case, at least onerecovery port 51 may be disposed in the vicinity below that inclinedbottom surface. In addition, making that inclined bottom surface liquidrepellent in advance makes it possible to recover the liquid inside thegroove portion 55 more reliably.

In addition, in the first through fifth embodiments discussed above, thenumber and arrangement of the recovery ports of the measurement stageST2 can be suitably modified.

In addition, in the first through fifth embodiments discussed above, therecovery ports can also be made movable in the Z axial directions.

In addition, in the first through fifth embodiments discussed above, therecovery ports can also be formed with a lyophilic material (e.g., ametal such as titanium).

In addition, in the first through fifth embodiments discussed above, ifa plurality of the recovery ports 51 is provided along the X axialdirections, then a lyophilic fine groove (e.g., having a width ofapproximately 0.5 mm) may be formed in, for example, the bottom surfaceof the groove portion 55, wherein the plurality of recovery ports 51 areformed, or in the stage upper surface F2 so as to connect adjoiningrecovery ports. In this case, the liquid inside that fine groove iscollected by the capillary phenomenon, and can be efficiently recoveredfrom the recovery ports 51.

In addition, in the first through fifth embodiments discussed above,moving the recovery ports 51 (groove portion 55) when recovering theliquid in the space of the optical path on the image plane side of theprojection optical system PL from the recovery ports 51 (groove portion55) makes it possible to recover the liquid more reliably. For example,the liquid can be recovered from the recovery ports 51 (groove portion55) while, for example, alternately moving the measurement stage ST2(substrate stage ST1) in the +Y and the −Y directions.

In addition, in the first through fifth embodiments discussed above, theplate member T of the substrate stage ST1 is detachably configured, butit does not necessarily need to be detachable, and may be integrallyformed with the base material PHB.

In addition, in the first through fifth embodiments discussed above, therecovery ports 51 are provided to the measurement stage ST2, but theymay be provided to the substrate stage ST1 instead of the measurementstage ST2, or they may be provided to each of the two stages.

In addition, in the first through fifth embodiments discussed above, itis preferable to provide in advance a buffer space of a prescribedvolume, for example, along the recovery pipe 23 between the vacuumsystem (suction system) and the recovery ports 22 of the liquid recoverymechanism 20, or along the passageway 52 between the vacuum system(suction system) 53 and the recovery ports 51. The provision of such abuffer space makes it possible to continue the suction (recovery) of theliquid inside, for example, the recovery pipe 23 or the groove portion55 (passageway 52) for a prescribed time because that buffer space isnegatively pressurized even if the air intake (exhaust air) operation bythe vacuum system is stopped due to, for example, a power failure.

In addition, each of the embodiments discussed above can also be adaptedto a so-called multistage type exposure apparatus, which comprises aplurality of (e.g., two) movable substrate stages that each holds thesubstrate P, as disclosed in, for example, Japanese Unexamined PatentApplication, Publication No. H10-163099, Japanese Unexamined PatentApplication, Publication No. H10-214783, and Published JapaneseTranslation No. 2000-505958 of the PCT International Application.

As discussed above, the liquid LQ in the present embodiment is purewater. Pure water is advantageous because it can be easily obtained inlarge quantities at, for example, a semiconductor fabrication plant, anddoes not adversely impact, for example, the optical element (lens) andthe photoresist on the substrate P. In addition, because pure water doesnot have an adverse impact on the environment and has an extremely lowimpurity content, it can also be expected to have the effect of cleaningthe upper surface of the substrate P and the tip surface of the opticalelement of the projection optical system PL. Furthermore, the exposureapparatus may be provided with an ultrapure water manufacturingapparatus if the pure water supplied from, for example, the plant is oflow purity.

Further, the refractive index n of pure water (water) with respect tothe exposure light EL that has a wavelength of approximately 193 nm issaid to be substantially 1.44; therefore, the use of ArF excimer laserlight (193 nm wavelength) as the light source of the exposure light ELshortens the wavelength on the substrate P to 1/n, i.e., approximately134 nm, and thereby a high resolution is obtained. Furthermore, becausethe depth of focus increases approximately n times, i.e., approximately1.44 times, that of in air, the numerical aperture of the projectionoptical system PL can be further increased if it is preferable to ensurea depth of focus that is approximately the same as that when used inair, and the resolution is also improved from this standpoint.

The projection optical system of the embodiments discussed above fillsthe liquid in the space of the optical path on the image plane side ofthe tip optical element, but it is also possible to employ a projectionoptical system that also fills the liquid in the space of the opticalpath on the mask side of the tip optical element, as disclosed in PCTInternational Publication No. WO2004/019128.

Furthermore, although the liquid LQ in the present embodiment is water,it may be a liquid other than water; for example, if the light source ofthe exposure light EL is an F₂ laser, then this F₂ laser light will nottransmit through water, so it would be acceptable to use as the liquidLQ a fluorine based fluid that is capable of transmitting F₂ laserlight, such as perfluorinated polyether (PFPE) or fluorine based oil. Inthis case, the parts (components) that make contact with the liquid LQare treated in order to make them lyophilic by forming a thin film with,for example, a substance that has a molecular structure that containsfluorine and that has low polarity. In addition, it is also possible touse as the liquid LQ a liquid (e.g., cedar oil) that is transparent tothe exposure light EL, has the highest possible refractive index, and isstable with respect to the projection optical system PL and thephotoresist coated on the front surface of the substrate P. In this caseas well, the surface treatment is performed in accordance with thepolarity of the liquid LQ used.

Furthermore, the substrate P in each of the abovementioned embodimentsis not limited to a semiconductor wafer for fabricating semiconductordevices; for example, a glass substrate for a display device, a ceramicwafer for a thin film magnetic head, a mask or the original plate of areticle (synthetic quartz, silicon wafer) used by an exposure apparatuscan be employed as the substrate P.

The exposure apparatus EX can also be adapted to a step-and-scan typescanning exposure apparatus (scanning stepper) that scans and exposesthe pattern of the mask M by synchronously moving the mask M and thesubstrate P, as well as to a step-and-repeat type projection exposureapparatus (stepper) that performs full field exposure of the pattern ofthe mask M with the mask M and the substrate P in a stationary state,and sequentially steps the substrate P.

In addition, the exposure apparatus EX can also be adapted to anexposure apparatus that uses a projection optical system (e.g., adioptric projection optical system, which does not include a reflectingelement, with a ⅛ reduction magnification) to perform full fieldexposure of a reduced image of a first pattern onto the substrate P in astate wherein the first pattern and the substrate P are substantiallystationary. In this case, the exposure apparatus EX can also be adaptedto a stitching type full field exposure apparatus that subsequentlyfurther uses that projection optical system to perform full fieldexposure of a reduced image of a second pattern, in a state wherein thesecond pattern and the substrate P are substantially stationary, ontothe substrate P so that the second pattern partially overlaps the first.In addition, the stitching type exposure apparatus can also be adaptedto a step-and-stitch type exposure apparatus that transfers at least twopatterns onto the substrate P so that they partially overlap, andsequentially steps the substrate P.

The type of exposure apparatus EX is not limited to semiconductor devicefabrication exposure apparatuses that expose the pattern of asemiconductor device on the substrate P, but can also be widely adaptedto exposure apparatuses for fabricating liquid crystal devices ordisplays, and exposure apparatuses for fabricating, for example, thinfilm magnetic heads, imaging devices (CCDs), or reticles and masks.

The exposure apparatus EX of the embodiments in the present applicationis manufactured by assembling various subsystems, including eachconstituent element recited in the claims of the present application, sothat prescribed mechanical, electrical, and optical accuracies aremaintained. To ensure these various accuracies, adjustments areperformed before and after this assembly, including an adjustment toachieve optical accuracy for the various optical systems, an adjustmentto achieve mechanical accuracy for the various mechanical systems, andan adjustment to achieve electrical accuracy for the various electricalsystems. The process of assembling the exposure apparatus from thevarious subsystems includes the mutual mechanical connection of thevarious subsystems, the wiring and connection of electrical circuits,the piping and connection of the atmospheric pressure circuit, and thelike. Naturally, before the process of assembling the exposure apparatusfrom these various subsystems, there are also the processes ofassembling each individual subsystem. When the process of assembling theexposure apparatus from the various subsystems is complete, acomprehensive adjustment is performed to ensure the various accuraciesof the exposure apparatus as a whole. Furthermore, it is preferable tomanufacture the exposure apparatus in a clean room wherein, for example,the temperature and the cleanliness level are controlled.

As shown in FIG. 15, a micro-device, such as a semiconductor device, ismanufactured by: a step 201 that designs the functions and performanceof the micro-device; a step 202 that fabricates a mask (reticle) basedon this design step; a step 203 that fabricates a substrate, which isthe base material of the device; a substrate processing step 204 thatincludes a process wherein the exposure apparatus EX of the embodimentsdiscussed above exposes a pattern of the mask onto the substrate; adevice assembling step 205 (comprising a dicing process, a bondingprocess, and a packaging process); an inspecting step 206; and the like.

The invention claimed is:
 1. A lithographic apparatus comprising: aprojection system by which a patterned radiation beam is projected ontoa substrate; a liquid confinement system which is configured to at leastpartly confine liquid in a space beneath the projection system, theliquid confinement system having an inlet and an outlet, the inlet beingconfigured to supply the liquid to beneath a lower surface of the liquidconfinement system, the outlet being disposed to surround the inlet andbeing configured to remove the liquid from beneath the lower surface; atleast a first stage and a second stage; a positioning system configuredto move the first stage and the second stage; a controller configured tocontrol the positioning system; and a channel system, wherein: thecontroller controls the positioning system to perform a joint scanmovement in which the first stage and the second stage cooperate whilemoving between a first situation and a second situation, the liquidbeing confined between the first stage and the projection system in thefirst situation and the liquid being confined between the second stageand the projection system in the second situation, such that during thejoint scan movement the liquid is essentially confined within the spacebeneath the projection system, the first stage has a first immersioncross edge at or near a side of the first stage, the second stage has asecond immersion cross edge at or near a side of the second stage, thefirst immersion cross edge and the second immersion cross edge beingface-to-face with each other with a gap between the immersion crossedges during the joint scan movement of the first and second stages, thefirst stage has a first lower portion located below the first immersioncross edge of the first stage, the first lower portion protrudingoutward beyond the first immersion cross edge and being stationaryrelative to the first immersion cross edge, the second stage has asecond lower portion located below the second immersion cross edge ofthe second stage, the second immersion cross edge of the second stageprotruding outward beyond the second lower portion to form an overhangportion of the second stage, the overhang portion having the secondimmersion cross edge of the second stage, during the joint scanmovement, the first lower portion of the first stage is disposed belowthe gap and at least a part of the first lower portion is disposed underthe overhang portion of the second stage, and the channel system has anopening provided at the first lower portion of the first stage, and thechannel system is configured to drain the liquid that passes through thegap formed between the first and second immersion cross edges during thejoint scan movement via the opening.
 2. The lithographic apparatusaccording to claim 1, wherein the liquid is confined between thesubstrate held by the first stage of the two stages and the projectionsystem in the first situation.
 3. The lithographic apparatus accordingto claim 2, wherein the second stage holds another substrate.
 4. Thelithographic apparatus according to claim 2, wherein the first stage ismoved away from under the projection system to a substrate-exchangeposition in the second situation.
 5. The lithographic apparatusaccording to claim 2, wherein in the first situation, the second stagestays for a period of time at a position away from under the projectionsystem while moving the first stage under the projection system.
 6. Thelithographic apparatus according to claim 2, wherein the second stage ismoved away from the first stage while the first stage is moved under theprojection system in the first situation, and the first stage and thesecond stage are moved close to each other before the second situationand before the first stage is moved away from under the projectionsystem.
 7. A device manufacturing method comprising: exposing asubstrate to a patterned beam through the projection system of thelithographic apparatus of claim 1; and processing the exposed substrate.8. The lithographic apparatus according to claim 1, wherein during thejoint scan movement, an upper surface of the first stage is adjacent toan upper surface of the second stage via the gap.
 9. The lithographicapparatus according to claim 8, wherein a positional relationshipbetween the upper surface of the first stage and the part of the firststage disposed under the overhang portion is substantially fixed. 10.The lithographic apparatus according to claim 1, wherein during thejoint scan movement, an upper surface of the first stage is adjacent toan upper surface of the second stage via the gap, and the overhangportion has the upper surface of the second stage.
 11. The lithographicapparatus according to claim 1, wherein the opening is connected to avacuum system, and gas and the liquid are separated from each otherbetween the opening and the vacuum system.
 12. The lithographicapparatus according to claim 1, wherein the second stage has a pluralityof support portions configured to support the substrate and a wallportion that is disposed to surround the support portions, the secondstage being configured to hold the substrate on the support portions bysucking a gas from a space surrounded by the wall portion and a bottomsurface of the substrate supported by the support portions.